1. Field of the Invention
The present invention relates to a shelf storage system, in which the goods to be stored are housed on a mobile storage and transport unit in shelves equipped with bars, conveying mechanisms being provided for transport of the goods in the storage system and auxiliary mechanisms for loading and unloading of the shelves and also for the drive, braking, position maintaining, counting and position changing of the storage and transport units.
2. Description of the Prior Art
Known systems of this type generally utilise load bearing members designated as roller bases, which are generally constructed as a latticed grill or wooden plate comprising wheels or rolls disposed in the vicinity of the four corners. The goods to be stored are then deposited on these roller supports and are housed on the shelf together with the base. In many cases, the goods to be stored are delivered onto conventional trays or palettes and, therefore, for the sake of simplicity, the loaded tray or palette is disposed on the roller base and thus stored.
This known method of storage has the advantage that the stored goods can be easily manipulated and can be put into and taken out of storage at relatively low cost. Owing to the mobility of the individual stored units, the provision of conveyor belts or similar transport mechanisms becomes superfluous, merely lifting mechanisms are required, for the loading and unloading of the shelves.
Although this system has given good results, it has some disadvantages. When loaded trays are disposed on the bases, a relatively large amount of space is lost in the upward sense, that is to say approximately 10-25 percent of the available storage area is taken up by the bases and the trays. Furthermore, these roller bases are relatively heavy and expensive, which is a particularly important disadvantage as they are required in large numbers.
There is the further disadvantage that, in most cases, they represent a more or less advantageous compromise in respect of adaptation to the type of goods to be stored, on one hand, and in respect of the mechanical operations taking place in the storage system on the other hand.